[PATCH v3 3/5] tests/cgroup: use cgroup.kill in cg_killall()

[Christian Brauner <brauner@kernel.org>]

From: Christian Brauner <christian.brauner@ubuntu.com>

If cgroup.kill file is supported make use of it.

Link: https://lore.kernel.org/r/20210503143922.3093755-3-brauner@kernel.org
Cc: Tejun Heo <tj@kernel.org>
Cc: cgroups@vger.kernel.org
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
/* v2 */
- Roman Gushchin <guro@fb.com>:
  - Fix whitespace.

/* v3 */
unchanged
---
 tools/testing/selftests/cgroup/cgroup_util.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 027014662fb2..f60f7d764690 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -252,6 +252,10 @@ int cg_killall(const char *cgroup)
 	char buf[PAGE_SIZE];
 	char *ptr = buf;
 
+	/* If cgroup.kill exists use it. */
+	if (!cg_write(cgroup, "cgroup.kill", "1"))
+		return 0;
+
 	if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
 		return -1;
 
-- 
2.27.0